I'm trying to understand a curious performance problem I observe in my QtQuick 
apps.

First off, here's something good:  If I have a simple app that contains one 
Knob widget, editing that knob causes 'top' to show a CPU% of ~7% (typical) and 
~15% (max).  When the app is idle, top reports CPU% of 0.  This is all good.

However, if I add 20 different widgets to the app, then do the same edit test 
on that single Knob, 'top' shows a CPU range that is now in the ~30-40% range 
and ~45% (max).    When the app is idle, top again reports CPU% of 0.

Why does the single edited Knob appear to use so much more processing power 
when there are a number of other idle widgets in the QtQuick app?

I am observing this on a BeagleBoard-xM, which is a supported platform for Boot 
to Qt.  I have cross-built Qt 5.2 for ARM with configure -release.  The 
BeagleBoard-xM is running at top speed on the GPU and CPU (400/1000).  DVFS 
features are not engaged.

I really needs to find out if I can make a Qt Quick app which runs on the BB-xM 
that can have a couple dozen widgets and when I use one of them, it will not 
use so much of the CPU.


Does anybody have any ideas how to avoid this problem?

- VStevenP
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